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When to Plant Lemon Balm in Gallatin County, MT

Gallatin County, Montana Zone 5a May

This month in Gallatin County, Montana

Here's what deserves your attention in Gallatin County, Montana this month. Everything below is tailored to Zone 5a and timed around your local frost dates.

Avg. last frost June 8
Avg. first frost September 19
Soil temp (4") 27°F
Watering High
Pest pressure Low
Daylight 14.7 hrs
Looking ahead to June
  • Transplants going out: lemon balm

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Lemon balm is a vigorous perennial herb with bright green, lemon-scented leaves. It makes a refreshing tea and is easy to grow but can spread aggressively.

Gallatin County, Montana is in USDA Zone 5a. The average last spring frost is June 8 and the first fall frost is September 19, giving you a growing season of approximately 103 days.

At an elevation of 8,376 feet, Gallatin County receives approximately 12.4 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Lemon Balm to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Lemon Balm successfully. Mulch heavily to conserve soil moisture.

Gallatin County, MT (Zone 5a) Short season
103 days
Last Spring Frost June 8
103 growing days
First Fall Frost September 19

Gallatin County Soil Profile

Soil Type

Loam

Soil pH

6.2-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Jun 1 🍅 Harvest: Aug 3 – Sep 21
Recommended (50%) ✗ May not fit
Transplant: Jun 15 🍅 Harvest: Aug 17 – Oct 5
Safe Start (90%) ✗ May not fit
Transplant: Jun 27 🍅 Harvest: Aug 29 – Oct 17

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Gallatin County

How your county's soil matches Lemon Balm's growing requirements.

Soil pH

Your soil pH (6.2–8.1) overlaps with Lemon Balm's range (5.5–7.5), though not a perfect match.

Soil Texture

The loam soil in Gallatin County is excellent for Lemon Balm — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Lemon Balm.

How to Plant Lemon Balm

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.5″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Lemon Balm

Lemon Balm needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Lemon Balm Needs Rainfall You Supplement Action
Jan 0.8" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.1" 0" ❄️ Dormant
Apr 1.3" 0" ❄️ Dormant
May 1.3" 0" ❄️ Dormant
Jun 2.2" 0.8" 1.4" 🚿 Regular watering
Jul 2.2" 1" 1.2" 🚿 Regular watering
Aug 2.2" 1.5" 0.7" 💧 Light watering
Sep 2.2" 1" 1.2" 🚿 Regular watering
Oct 1.1" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Gallatin County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Lemon Balm Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Lemon Balm needs ~748 GDD — county provides 1,184 GDD Excellent fit

Lemon Balm Planting Timeline — Gallatin County, MT

Lemon Balm Planting Calendar

Activity When Date Range
Transplant Outdoors June 15 Jun 15 – Jun 29
Harvest August 17 Aug 17 – Oct 5

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June Transplant Outdoors
July
August Harvest
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–70 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

103 days in Gallatin County

Growing Tips for Lemon Balm in Gallatin County

Direct sow Lemon Balm outdoors after June 08 in Gallatin County when soil has warmed and frost danger has passed.

General growing tips

Start from seed, cuttings, or divisions. Contain in pots or use barriers to prevent spreading. Harvest frequently to keep plants bushy and prevent flowering.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lemon Balm in Gallatin County, MT?

Gallatin County is in Zone 5a with an average last frost of June 8. Plan your Lemon Balm planting based on this frost date — see the calendar above for exact timing.

What planting zone is Gallatin County, MT?

Gallatin County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is June 8 and first fall frost is September 19.

🌱

Your Gallatin County Garden Planner — Free

A 24-page printable planner built for Gallatin County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Gallatin County, MT. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.